AboutSystem, Installer: show light/dark logos

* Use B_DOCUMENT_TEXT_COLOR and B_DOCUMENT_BACKGROUND_COLOR instead
of black on white in text views.

* Depending on HAIKU_DISTRO_COMPATIBILITY_OFFICIAL build flag, either
show the official Haiku logo or the Walter logo.

* If the official Haiku logo is used, show a version with black letters
if B_DOCUMENT_BACKGROUND_COLOR is light, and white letters if it's not.

* Remove the "installer" versions of the black-on-white Haiku logo.
Instead introduce "black|white-on-transparent" logos with a
transparent background.

* Fixed the leave shadows in logo Wonderbrush files. Especially the
yellow leave's shadow appeared too large and blurry.

Change-Id: I6d3ac384d2c96d91d35e6d6e85025c9e2064d59e
Reviewed-on: https://review.haiku-os.org/c/haiku/+/7419
Reviewed-by: waddlesplash <waddlesplash@gmail.com>